Air-heating furnace



2, 1930. c. w: swlNGLEY 1,774,734

AIR'HEATING FURNACE Filed nay 7, 192e I N u fa Patented Sept. 2, 1930 UNITED STATES PATENT OFFICE i AIR-HEATTNG FURNACE Application filed May "1, 1928.

This invention pertains to air heating furnaces, such as are used in domestic heating` plants.

Une of the objects of this invention is to provide an air heating furnace of improved efficiency and simplicity of operation.

Another object of this invention is to provide such a furnace with improved smoke controlling appliances so as to prevent smoking during firing operations.

Another object of this invention is to provide a furnace having hollow grate bars with arrangements whereby cold air is supplied to pass through said grate bars so as to prevent overheating of the same.

Further objects will appear from the following description, taken in connection with the accompanying drawing, in which- Figure 1 is a front View of a furnace em 2 bodying this invention; and

Figure 2 is a sectional view, showing the furnace with one side of the acket cut away.

Referring to the drawing 1 designates a lire boxy of any suitable construction. Traversing the fire box 1 from front to rear and in the upper portion thereof, is an upper grate, comprising a a series of hollow grate bars 2. The grate bars 2 may be constructed of cast iron or any other suitable material and are cast hollow, as shown in Figure 1, having a tapered cross section so that the top face of each is broader than the bottom. This provides that the space between the grate bars flaresr toward the bottom so that it will be impossible for coal particles to lodge between the grate bars. The grate bars 2 eX tend from the front of the lire boX and are set so as to incline upwardly toward the rear, passing through the upper portion of the lire box and opening at the rear ends to a space L in rear of the fire boX.

A lower grate 5 of any suitable construc tion is provided in the lower part of the fire box 1. Access to the grate 5y is provided through a door 6 in the front of the furnace. Below the grate 5 is an ash pit 7, to which access may be had by a door 8 in the front of the furnace. A draft door 9 is provided in the upper part of the lire boX above the grate 2. This door may be provided with a suit- Scrial No. 275,576.

able ratchet 10 or other device adapted to hold the door open at any desired angle.

Connected with the fire boX 1 between the upper and lower grates 2 and 5 is a flue 11. This Hue has a rising section 12 extending upwardly within the jacket 3, which encloses the lire box and this flue. At the top ofthe jacket the flue has a reverse bend 13 and then a downwardly extending section 14;, which connects at 15 with any suitable outlet, such as a stack or chimney. The section 12 rises within a short distance in the rear of the lire box 1 so as to provide the space l between it and the fire box into which the heated airvfrom the hollow grate bars 2 is discharged.

The upper part of the lire box 1 above the grate 2 is connected by means of a draft connection 16 with the bend 13 in the top of the flue. The draft connection 1G is normally closed by a damper 17 hinged at 1S on the fire box and having an arm 19 having connected thereto a manipulative link 2O passing through the front of lthe jacket and provided with a handle 21 for manipulation from' the front of the furnace. A second damper 22 is arranged to close the due 11. This damper is pvoted at 23 on the fire box and has an arm 24 connected by a link 25 with an arm 26 on the damper 17. The linlr 25 thus connects the two dampers together, so that they will be operated together by manipulation of the element 20. The connection is such that, when one of these dampersis open, the other is closed and vice versa.

Across the front of the lire box and so as to enclose the open ends of the grate bars 2 is a header 29 having inlet openings 30 at any convenient point, preferably in the bottom, as shown. Cold air pipes 31 connected te the header 29 at the inlets 30 pass downwardly within the casing to the rear thereof and their rear ent s extend a short distance into the cold air intake pipe 28. The pipes 31 thus receive a continual supply of cold, fresh air, taken directly from out-doors or other source to which the intake 2S leads, and this cold air is fed to the header 29 at spaced. points and in such a way as to distribute the supply uniformly amongst the grate bars 2. This cold air, passing through the hollow grate bars, is heated in its passage therethrough and thus keeps the temperature of the grate bars then'iselvcs at a sufficiently low value to avoid any danger of overheating or burning out.

fr water pan may be placed within the header 29 so as to supply moisture to the air in the l eader. This arrangement serves not only to humidify the air that is to be supplied to the rooms heated, but also increases the heat-absorbing capacity of the air passing through the grate bars 2. ylie moisture content of the air that passes through the grate bars renders the air capable of al sorbing an increased amount of heat so that its effectiveness in keeping' down the teinperature of said grate bars is thereby increased. The water pan 33 may be arranged to receive a continual supply of water from any suitable source, such as the house water supply 35, and any suitable automatic regulating device 84; may be provided whereby the level of the water in the pan is maintained constant. Such devices are well known in Vthe art and need not be described in detail.

ln the use of this furnace, zhe fuel is placed upon the upper grate i2, acces to this grate being provided through a door Qi" upon which the draft door 9 n'iounted. 'lihe fuel burns upon the grate 2. The draft enters at the door 9, and, passing downwardly through thel grate 2, passes out through the fine ll. As the fuel particles are reduced in size, they fall through the grate i upon the lower grate 5. which is thus continually supplied with a bed of glowing` coals at a high temperature. The fumes from the grate 2, which may contain considerable combustible mater, such as smoke, are thus passed into the high temperature chamber above the grate 5, together with a supply of ai r from the draft door 9, and at this high temper; ture the smoke is entirely consumed and its heating value added to that of the remainder of the fuel. lhe products of combustion then pass out through the flue. ll, l2, 1,3, lll. Upon leaving the tire box, these gases are at a very high temperature, and, they pass through the extended portion of the flue which is contained within `the jacket 3, their heating value is utilized to heat the air within the jacket. the upward and downward sections, together with the reverse bend in the flue, providing additional heating surface, which is kept a high temperature by 'the flue gases. At the same time air passing into the hollow grate bars from outside of the jacket in front of tl fui becomes heated thereby and. on account of the upward inclination of these tubes, flows rearwardl7 therethrough and discharges into the space 4, which thus becomes a hot pocket surrounded on all sides by heating surfaces and receiving the heated air from the hollow bars 2. There is thus provided an intensive heating unit within the jacket 3. Cold air entering the jacket at the inlet 28, which may be connected vith out-door air or any other suitable supply of fresh air, is heated by Contact with the jacket and the tlues ll, l2, le, and mingled with the hot air discharged by the grate bars 2. The entire mass of entering air thus becomes hot and, rising to the top of the jacket, passes outuf'ardly through the hot air pipes 40 to the various rooms to be heated.

In order to prevent the reversal of draft through the grate 2, upon opening of one of zhe doors (i or 8 for the purpose of firing operations, from causing a discharge of smoke from the draft opening 9, the dampers 17 and 22 may be manipulated to close the flue l1 and open the connection 16 so that the draft may carry the smoke through said connection to Vthe section 13 and out through the flue lll. in this way, objectionable smoking of the furnace during tiring operations is obviated. The rflampers 1T and are connected together so that the same manipulation of the element 2O operates both dampers in proper relation to one another.

TVhile this furnace has been described as a unitary structure, forming a complete heating` plant, it will be obvious that certain subcombinations can be used alone or without reference to other sub-conibiiuitions and that the separate use of such sub-combinations is contemplated by 'this invention. It is further obvious that various changes may be made, within the scope of the appended claims, in the details of construction without departing from the spirit of this invention. lt is, therefore, to be understood that this invention is not to be limited to the specific details shown and/or described.

Having thus described the invention, what is claimed is:

l. An air heating furnace, comprising. a fire box, a hollow upper grate, a lower grate, a draft inlet to said tire bof; abo Je said upper grate, an outlet fiue connected to said tire box between said grates, said tine extending upwardly adjacent said lire boi; and .said hollow grate being` positioned to discharge heat'- ed air into the space between said flue and .said fire box, and an air jacket eiiclosing said lire bof; and said tine.

Q. An air heating furnace, comprising, a tire box, a hollow ujiper grate, a. lower grate, a draft inlet to said tire bei; above said upper grate, an outlet flue connected to said lire box between said gratos, said i'iue extending upwardly adjacent said lire. box and said hollow grate being positioned to discharge heated air into the space between said flue and said tire box, a draft connection between said flue and said fire box above said upper grate, a damper in said connection, and an air jacket surrounding said fire box.

3. An air heating furnace, comprising, a. fire box, an upper grate having` a series of hollow grate bars, a lower grate, an outlet flue connected to said fire box, means for sup- Jlying cold air to said hollow grate bars to be heated thereby, and means for supplying the air so heated to a room.

4. An air heating furnace, comprising, a tire box, an upper grate having a series of hollow grate bars, a lower grate, an outlet iue connected to said ire box, a header connecting the ends of said hollow grate bars, a cold air intake, means for connecting said header with said intake so as to supply cold air to said hollow grate bars to be heated thereby, and means for supplying the air so heated to a room.

5. An air heating furnace, comprising, a fire box, an upper grate having a series of hollow grate bars, a lower grate, an outlet flue connected to said fire box, a header connecting the ends of said hollow grate bars, a Cold air intake, means for connecting` said header at spaced points thereof with said intake so as to supply cold air to said hollow grate bars to be heated thereby, and means for supplying the air so heated to a room.

6. An air heating furnace, comprising, a lire box, an upper grate having a series of hollow grate bars, a lower grate, an outlet flue connected to said fire box, an air jacket en` closing said lire box adapted to receive the heated air from said hollow grate bars and having a cold air intake, and a duct from said intake adapted to supply air to said ho'llow grate bars.

7. An air heating furnace, comprising, a lire box, an upper grate having a series of hollow grate bars, a lower grate, an outlet flue connected to said fire box, an air jacket enclosing said lire box adapted to receive the heated air from said hollow grate bars and having a cold air intake, and a lduct within said jacket leading from said intake adapted to supply air to said hollow grate bars.

8. An air heating furnace, comprising, a lire box, a grate therein having a series of hollow grate bars, a header connecting said grate bars,ajacketenclosingsaidfre box adaptedto receive the heated air from said hollow grate bars and having a cold air inlet, and a plurality of air ducts receiving air from said inlet and connecting with said header at symmetrically spaced points with respect to said grate bars.

In testimony whereof I aix my signature this 24th day of April, 1928.

CHARLES W. SVINGLEY, 

